Error found:
in module Main
at tests/purs/failing/InstanceSigsBodyIncorrect.purs:10:9 - 10:13 (line 10, column 9 - line 10, column 13)

  Could not match type
           
    Boolean
           
  with type
          
    Number
          

while checking that type Boolean
  is at least as general as type Number
while checking that expression true
  has type Number
in value declaration fooNumber

See https://github.com/purescript/documentation/blob/master/errors/TypesDoNotUnify.md for more information,
or to contribute content related to this error.